High Degree Of Freedom Research Articles

Template Assisted Synthesis of Linear [5]Catenane by Post-Functionalization of Templated [2]Catenane and Using Click Reaction.

Polymers with all mechanically interlocked rings, such as linear [n]catenanes, have great potential as functional materials due to possible higher degrees of freedom that may contribute to their flexibility but remain elusive. All the synthetic methods used to prepare such a polymer yield mixtures of products. In the absence of higher molecular weight linear [n]catenanes, emphasis on synthesizing low molecular weight oligomers is being pursued. Here, we have described the synthesis of a linear [5]catenane by post-functionalizing a Co(III) templated [2]catenane having a pyridine-diamide unit free for further metal ion coordination. Two molecules were synthesized with suitable threading groups: one, two terminal azide groups, and two, with two terminal alkyne groups to form two [3]pseudorotaxane utilizing Co(III) coordination. These units were then joined, forming a macrocycle, using click reaction, giving the desired metalated linear [5]catenane in 40 % yield. Removal of metal ions leads to linear [5]catenane. In addition, the formation of linear [3] and [2]catenane are also observed. All synthesized structures have been isolated by column chromatographic technique and characterized by 1H-NMR, 13C-NMR, and mass spectroscopy.

Expansions of the theatre at the times of quantum: Temptation by radicalism

Relevance. This article explores the emerging field of �quantum theatre� and critically examines attempts to apply quantum concepts to theatrical theory and practice. Purpose. This article aims to evaluate the current state of quantum theatre research and propose new theoretical frameworks. Methodology. The author conducts a critical analysis of existing literature on quantum theatre, including works by Carol Fisher, Naomi Iizuka, Anne Bogart, and others. The methodology involves examining these works through the lens of quantum physics principles, while cautioning against simplistic analogies. Results. The analysis reveals that many current approaches to quantum theatre rely on superficial analogies to quantum phenomena without sufficient rigor. The author argues there is not yet a true �quantum theatre�, but rather early explorations of quantum-inspired ideas. The author proposes new theoretical frameworks drawing on Rupert Sheldrake�s morphogenetic fields and V.V. Nalimov�s �fields of consciousness� to understand theatrical phenomena. Conclusions. This article concludes that more rigorous interdisciplinary approaches drawing on quantum physics, biology, and consciousness studies offer promising directions for future research. The author suggests that theatre and artistic culture in general as open non-linear systems operating based on self-organization, self-regulation and self-development, with high degrees of freedom, can provide a unique understanding of quantum phenomena at the macro level, potentially contributing to the fundamental principles of cognitive theory. Keywords: morphogenetic fields; quantum biology; non-linear theatre; space-time in performance; post-non-classical art science

3D Intelligent Cloaked Vehicle Equipped with Thousand-Level Reconfigurable Full-Polarization Metasurfaces.

A crucial aspect in shielding a variety of advanced electronic devices from electromagnetic detection involves controlling the flow of electromagnetic waves, akin to invisibility cloaks. Decades ago, the exploration of transformation optics heralded the dawn of modern invisibility cloaks, which has stimulated immense interest across various physical scenarios. However, most prior research is simplified to low-dimensional and stationary hidden objects, limiting their practical applicability in a dynamically changing world. This study develops a 3D large-scale intelligent cloak capable of remaining undetectable even in non-stationary conditions. By employing thousand-level reconfigurable full-polarization metasurfaces, this work has achieved an exceptionally high degree of freedom in sculpting the scattering waves as desired. Serving as the core computational unit, a hybrid inverse design enables the cloaked vehicle to respond in real-time, with a rapid reaction time of just 70ms. These experiments integrate the cloaked vehicle with a perception-decision-control-execution system and evaluate its performance under random static positions and dynamic travelling trajectories, achieving a background scattering matching degree of up to 93.3%. These findings establish a general paradigm for the next generation of intelligent meta-devices in real-world settings, potentially paving the way for an era of "Electromagnetic Internet of Things."

Integrating network pharmacology, bioinformatics, and experimental validation to unveil the molecular targets and mechanisms of galangin for treating hepatocellular carcinoma

BackgroundGalangin, a flavonoid compound, is derived from Alpinia officinarum Hance. Previous studies have shown that galangin can inhibit the proliferation of hepatocellular carcinoma (HCC), but its mechanism is still unclear. This study aims to investigate the potential targets and molecular mechanisms of galangin on HCC through network pharmacology, bioinformatics, molecular docking, and experimental in vitro validation.MethodsIn this study, network pharmacology was used to investigate the targets and mechanisms of galangin in the treatment of HCC. AutoDockTools software was used to simulate and calculate the binding of galangin to its core targets. GO and KEGG enrichment analyses were conducted in the DAVID database to explore the main biological functions and signaling pathways impacted by galangin intervention. In addition, bioinformatics was applied to examine the correlation between the differential expressions of the anti-HCC core targets of galangin and the survival of patients with HCC. Finally, the findings obtained from network pharmacology and bioinformatics were verified in cell experiments.ResultsA total of 67 overlapping target genes of galangin and HCC were identified. Through the analysis of the protein-protein interaction (PPI) network, 10 hub genes with the highest degree of freedom were identified, including SRC, ESR1, MMP9, CDK4, CCNB1, MMP2, CDK2, CDK1, CHK1, and PLK1. These genes were found to be closely related to the degradation of the extracellular matrix, signal transduction, and the cell cycle. GO and KEGG enrichment analyses revealed that galangin exerts an anti-HCC role by affecting various signaling pathways, including the cell cycle, pathways in cancer, and the PI3K-Akt signaling pathway. The results of molecular docking indicated a significant interaction between galangin and CCNB1, CDK4, CDK1, and PLK1. Bioinformatics analysis revealed that CCNB1, CDK4, CDK1, and PLK1 were upregulated in the liver of patients with HCC at both the mRNA and protein levels. Flow cytometry analysis showed that galangin induced G0/G1 phase arrest and cell apoptosis in HepG2 and Huh7 cells. Additionally, galangin suppressed the expression of key proteins and mRNAs involved in the cell cycle pathway.ConclusionsThese results suggest that galangin inhibits the growth of HCC cells by arresting the cell cycle at the G0/G1 phase.

Coordinated torque control for enhanced steering and stability of independently driven mobile robots

PurposeMobile robots with independent wheel control face challenges in steering precision, motion stability and robustness across various wheel and steering system types. This paper aims to propose a coordinated torque distribution control approach that compensates for tracking deviations using the longitudinal moment generated by active steering.Design/methodology/approachBuilding upon a two-degree-of-freedom robot model, an adaptive robust controller is used to compute the total longitudinal moment, while the robot actuator is regulated based on the difference between autonomous steering and the longitudinal moment. An adaptive robust control scheme is developed to achieve accurate and stable generation of the desired total moment value. Furthermore, quadratic programming is used for torque allocation, optimizing maneuverability and tracking precision by considering the robot’s dynamic model, tire load rate and maximum motor torque output.FindingsComparative evaluations with autonomous steering Ackermann speed control and the average torque method validate the superior performance of the proposed control strategy, demonstrating improved tracking accuracy and robot stability under diverse driving conditions.Research limitations/implicationsWhen designing adaptive algorithms, using models with higher degrees of freedom can enhance accuracy. Furthermore, incorporating additional objective functions in moment distribution can be explored to enhance adaptability, particularly in extreme environments.Originality/valueBy combining this method with the path-tracking algorithm, the robot’s structural path-tracking capabilities and ability to navigate a variety of difficult terrains can be optimized and improved.

Ex vivo validation of magnetically actuated intravascular untethered robots in a clinical setting

Intravascular surgical instruments require precise navigation within narrow vessels, necessitating maximum flexibility, minimal diameter, and high degrees of freedom. Existing tools often lack control during insertion due to undesirable bending, limiting vessel accessibility and risking tissue damage. Next-generation instruments aim to develop hemocompatible untethered devices controlled by external magnetic forces. Achieving this goal remains complex due to testing and implementation challenges in clinical environments. Here we assess the operational effectiveness of hemocompatible untethered magnetic robots using an ex vivo porcine aorta model. The results demonstrate a linear decrease in the swimming speed of untethered magnetic robots as arterial blood flow increases, with the capability to navigate against a maximum arterial flow rate of 67 mL/min. The untethered magnetic robots effectively demonstrate locomotion in a difficult-to-access target site, navigating through the abdominal aorta and reaching the distal end of the renal artery.

Development of a musculoskeletal shoulder model considering anatomic joint structures and soft-tissue deformation for dynamic simulation.

The shoulder joint has a high degree of freedom and an extremely complex and unstable kinematic mechanism. Coordinated contraction of the rotator cuff muscles that stop around the humeral head and the deltoid muscles and the extensibility of soft tissues, such as the joint capsule, labrum, and ligaments, contribute to shoulder-joint stability. Understanding the mechanics of shoulder-joint movement, including soft-tissue characteristics, is important for disease prevention and the development of a device for disease treatment. This study aimed to create a musculoskeletal shoulder model to represent the realistic behavior of joint movement and soft-tissue deformation as a dynamic simulation using a rigid-body model for bones and a soft-body model for soft tissues via a spring-damper-mass system. To reproduce the muscle-contraction properties of organisms, we used a muscle-expansion representation and Hill's mechanical muscle model. Shoulder motion, including the movement of the center of rotation in joints, was reproduced, and the strain in the joint capsule during dynamic shoulder movement was quantified. Furthermore, we investigated narrowing of the acromiohumeral distance in several situations to induce tissue damage due to rotator cuff impingement at the anterior-subacromial border during shoulder abduction. Given that the model can analyze exercises under disease conditions, such as muscle and tendon injuries and impingement syndrome, the proposed model is expected to help elucidate disease mechanisms and develop treatment guidelines.

Adjoint Algorithm Design of Selective Mode Reflecting Metastructure for BAL Applications.

Broad-area lasers (BALs) have found applications in a variety of crucial fields on account of their high output power and high energy transfer efficiency. However, they suffer from poor spatial beam quality due to multi-mode behavior along the waveguide transverse direction. In this paper, we propose a novel metasurface waveguide structure acting as a transverse mode selective back-reflector for BALs. In order to effectively inverse design such a structure, a digital adjoint algorithm is introduced to adapt the considerably large design area and the high degree of freedom. As a proof of the concept, a device structure with a design area of 40 × 20 μm2 is investigated. The simulation results exhibit high fundamental mode reflection (above 90%), while higher-order transverse mode reflections are suppressed below 0.2%. This is, to our knowledge, the largest device structure designed based on the inverse method. We exploited such a device and the method and further investigated the device's robustness and feasibility of the inverse method. The results are elaborately discussed.

Learning control for body caudal undulation with soft sensory feedback

Soft bio-mimetic robotics is a growing field of research that seeks to close the gap with animal robustness and adaptability where conventional robots fall short. The embedding of sensors with the capability to discriminate between different body deformation modes is a key technological challenge in soft robotics to enhance robot control–a difficult task for this type of systems with high degrees of freedom. The recently conceived Linear Repetitive Learning Estimation Scheme (LRLES)–to be included in the traditional Proportional–integral–derivative (PID) control–is proposed here as a way to compensate for uncertain dynamics on a soft swimming robot, which is actuated with soft pneumatic actuators and equipped with soft sensors providing proprioceptive information pertaining to lateral body caudal bending akin to a goniometer. The proposed controller is derived in detail and experimentally validated, with the experiment consisting of tracking a desired trajectory for the bending angle envelope while continuously oscillating with a constant frequency. The results are compared vis a vis those achieved with the traditional PID controller, finding that the PID endowed with the LRLES outperforms the PID controller (though the latter has been separately tuned) and experimentally validating the novel controller’s effectiveness, accuracy, and matching speed.

A facile route for decoration of hematite photoanodes by transition metal hydroxide co‐catalysts

AbstractEarth‐abundant α‐Fe2O3 (hematite) is a convincing photoanode for photoelectrochemical (PEC) water splitting; however, its intrinsic properties of inferior charge transfer and sluggish water oxidation kinetics limit its performance. Here, we report a straightforward decoration method for transition metal hydroxides to accelerate the oxygen evolution reaction (OER) of hematite photoanodes grown by electric field‐assisted liquid phase deposition (EA‐LPD). The investigations revealed that Co(OH)2 acts as a superior co‐catalyst compared with hydroxides of Mn, Fe, Co, Ni, and Zn. EA‐LPD‐grown hematite photoanode loaded with cobalt hydroxide exhibited an excellent PEC performance. A photocurrent density of 0.93 mA.cm−2 at 1.23 V versus reversible hydrogen electrode was achieved for the modified hematite, ∼3 times more than that of pristine hematite, and a cathodic shift of 100 mV for the onset potential was observed. The proposed simple and cost‐effective co‐catalyst loading strategy provides a high degree of freedom in the design of co‐catalysts with a complex chemical composition comprising transition metal oxyhydroxides and hydroxides on different photoanodes for more efficient charge carrier separation for the PEC applications.

Shape Control of Elastic Deformable Linear Objects for Robotic Cable Assembly

Currently, cables are manually installed in aircraft manufacturing scenarios. The utilization of robots in cable assemblies can enhance efficiency and ensure quality, presenting great promise for the future. However, the assembly process must control the shape of the cables, which is a significant challenge for robots. On the one hand, cables have high degrees of freedom in space, making accurate modeling of cable dynamics for robotic arm manipulation difficult; on the other hand, cable deformation has uncertainty, and the applied forces cause simultaneous deformation and motion, which is difficult to control. To address these problems, this study proposes a cable‐shape control method based on graph neural networks and online visual shape‐servoing. The method first approximates cable dynamics with a graph neural network. Then, in practice, the learnt model is used alongside visual‐based shape‐servoing to generate optimal robotic arm movements, controlling the cable to attain the desired shape. In the experiments, precise control of three different cable types is realized, and an example of a completed cable assembly is shown.

Two‐Photon Direct Laser Writing of pNIPAM Actuators in Microchannels for Dynamic Microfluidics

Microfluidic tools enable to investigate and manipulate various chemical and biological processes at small scales. As a result, it finds widespread applications in lab‐on‐chip devices, drug delivery systems, or miniaturized cell cultures. However, microfluidic devices are still limited in their flexibility and are often designed to fulfill a single functionality. Moreover, technologies to introduce dynamic functionalities with high precision and at high resolution after the development of a continuous phase microfluidic chip remain scarce. Herein, two‐photon polymerization direct laser writing is introduced as a suitable approach to equip continuous phase microfluidic chips with structurally defined thermoresponsive poly(N‐isopropyl‐acrylamide) (pNIPAM) microactuators. Harnessing the lower critical phase transition temperature of pNIPAM, and upon controlling specific design parameters, the efficient catch and release of polystyrene beads of different sizes using a pNIPAM micropillar brush array is demonstrated. Moreover, a biocompatible pNIPAM microgripper array is designed to subsequently capture and release differently sized (single) cell populations. Overall, the method offers great flexibility and a high degree of freedom toward the fabrication of dynamic microfluidic devices with great adaptability to experimental conditions in real time.

Simplistic framework of single-pixel-programmable metasurfaces integrated with a capsuled LED array

Coding metasurfaces can manipulate electromagnetic wave in real time with high degree of freedom, the fascinating properties of which enrich the metasurface design with a wide range of application prospects. However, most of the coding metasurfaces are designed based on external excitation framework with the wired electrical or wireless light control devices, thus inevitably causing the interference with electromagnetic wave transmission and increasing the complexity of the metasurface design. In this work, a simplistic framework of single-pixel-programmable metasurfaces integrated with a capsuled LED array is proposed to dynamically control electromagnetic wave. The framework fully embeds the photoresistor in the meta-atom, controlling the LED array to directly illuminate the photoresistor to modulate the phase response. With this manner, the complex biasing network is transformed to the universal LED array, which means the physical control framework can be transformed to a software framework, and thus the functions of the metasurface can be freely manipulated by encoding the capsuled LED array avoiding mutual coupling of adjacent meta-atoms in real time. All the results verify that the far-field scattering pattern can be customized with this single-pixel-programmable metasurface. Encouragingly, this work provides a universal framework for coding metasurface design, which lays the foundation for metasurface intelligent perception and adaptive modulation.

Strongly correlated electron system NiWO4: A new family of materials for triboelectrics using inherent Coulombic repulsion

The strongly correlated electron system (SCES) insulators promise a wide range of intriguing physical phenomena arising from the exotic charge gap depending on the strength of the Coulombic repulsion between d and f orbital cations. The SCES exhibits polaron hopping conduction, which requires a higher activation energy for carrier conduction between nearest cations, indicating a strong insulating character with relatively high permittivity. Here, we demonstrate that the NiWO4 SCES insulator, which is formed by Coulombic repulsion between the nearest d orbital of Ni, proposes a suitable triboelectric material unlisted system from conventional metal oxides. The higher degree of freedom in NiWO4 by the lower symmetry of monoclinic structure and an additional selection of composition exhibits high relative permittivity (∼13.8) in a wide range of temperatures (up to 180 ℃). The optimized simple mixture of NiWO4 and PDMS (polydimethylsiloxane) for the negatively charged material to triboelectric nanogenerator (TENG) presents 1.78 times higher output compared to the pristine PDMS film-based TENG. NiWO4, considering the physical properties of the SCES determined by Coulombic repulsion strength, paves the way for a new option of TENG materials following the high permittivity.

Four-channel holographic metasurface based on frequency-angle multiplexing

Due to the powerful ability of metasurfaces to manipulate light fields, various optical parameters have been widely explored and studied through precise design of metasurface units. However, the angle of incidence, which is one of the important optical parameters, has not been fully investigated for multiplexing due to the lack of coding degrees of freedom. Here, the scheme of four-channel holographic metasurface based on frequency-angle multiplexing is proposed to achieve independent display of multiple images at different frequencies and angles. The metasurface units used are Metal-Insulator-Metal structures that can effectively manipulate the electromagnetic wave’s amplitude in the reflection space to accommodate various operating frequencies and angles of incidence. The effectiveness of the proposed four-channel holographic scheme is verified by encoding four independent amplitude image information into a metasurface array. The four-channel scheme proposed in this paper successfully breaks the limitation of angular correlation and improves the density and capacity of information storage. This not only provides a higher degree of freedom and flexibility for multi-channel metasurface holographic imaging, but also holds significant importance for advancing optical information processing and display technologies. It is believed that the metasurface based on frequency-angle multiplexing can easily find more promising applications, including electromagnetic wavefront control, encryption/ concealment of optical information, and multifunctional switchable devices.

Semi-symmetrical Coprime Linear Array with Reduced Mutual Coupling Effect and High Degrees of Freedom

Semi-symmetrical Coprime Linear Array with Reduced Mutual Coupling Effect and High Degrees of Freedom

Autonomous optimization of process parameters and in-situ anomaly detection in aerosol jet printing by an integrated machine learning approach

Aerosol jet printing (AJP) is a newly-developed technology for printed electronics in additive manufacturing (AM) industry. Compared to conventional printed electronics, AJP technology has the capability of fabricating high-resolution patterns (∼ 10 µm) with multiple materials and high degrees of freedom. However, insufficiently optimizing the printing process, including reliance on traditional trial-and-error methods and theoretical models, may lead to a decline in production quality, consequently limiting the widespread adoption of AJP technology. In this paper, an integrated machine learning approach is developed for autonomous optimization of process parameters and in-situ anomaly detection in AJP. In the developed approach, a coaxial camera is incorporated with a stepwise data-driven modeling approach for optimal operating window identification and process model development of AJP, thereby systematically optimizing the main process parameters prior to printing. Subsequently, a convolutional neural network (CNN) model is developed and integrated with an alignment camera for in-situ process monitoring and printing status evaluation, enabling the anomaly detection of the AJP process. Afterwards, leveraging process similarity through transfer learning allows rapid calibration of detected system drifts or variations in process stability, thereby enhancing the product consistency of AJP. Generally, by utilizing state-of-the-art machine learning techniques, the autonomous optimization of process parameters and anomaly detection in AJP achieve accuracies of 95.3% and 92.7%, respectively. This indicates the effectiveness and systematic nature of the developed approach compared to traditional trial-and-error methods and theoretical models. Furthermore, due to its data-driven characteristics, this approach has the potential to extend its applicability to other noncontact ink writing techniques, facilitating further research for process optimization in AM.

Remediation of toluidine blue O dye from aqueous solution using surface functionalized magnetite nanoparticles

Abstract In the current study, tannic acid-functionalized iron oxide nanoparticles have been synthesized using a cost-effective co-precipitation method and subsequently characterized using various instrumentation techniques such as Fourier transform infrared spectroscopy, X-ray diffractometer, field emission scanning electron microscopy, and thermal gravimetric analysis. Further, these surface-modified magnetite nanoparticles have been used for the adsorption of toluidine dye from an aqueous solution. The adsorption process was accompanied using batch procedure, and influences of several factors such as adsorbent dose, contact time, pH, temperature, and initial concentration of adsorbate were inspected concurrently. The maximum adsorption capacity of tannic acid-functionalized magnetite nanoparticles was found to be 50.68 mg/g. The adsorption process was observed to follow the Temkin isotherm model, whereas the kinetic study was well described by pseudo-second order. The thermodynamic study revealed the adsorption process to be endothermic and spontaneous in nature with a high degree of freedom between adsorbent and adsorbate. Therefore, the study indicated that the tannic acid-functionalized magnetite nanoparticles have promising adsorption capability and can be used as an excellent adsorbent for the removal of toluidine blue O dye from the aqueous solution.

Symmetric Double-Supplemented Nested Array for Passive Localization of Mixed Near-Field and Far-Field Sources

In mixed-field source localization, the physical properties of a sensor array, such as the degrees of freedom (DOFs), aperture, and coupling leakage, directly affect the accuracy of estimating the direction of arrival (DOA). Compared to conventional symmetric uniform linear arrays, symmetric non-uniform linear arrays (SNLAs) have a greater advantage in mixed-field source localization due to their larger aperture and higher DOF. However, current SNLAs require improvements in their physical properties through modifications to the array structure in order to achieve more accurate source localization estimates. Therefore, this study proposes a symmetric double-supplemented nested array (SDSNA), which translates nested subarrays based on symmetric nested arrays to increase the aperture and inserts two symmetric supplemented subarrays to fill the holes created by the translation. This method results in longer consecutive difference coarray lags and larger apertures. The SDSNA is compared to existing advanced SNLAs in terms of their physical properties and DOA estimation. The results show that, with the same number of sensors, the SDSNA has a higher DOF, a larger aperture, and smaller coupling, indicating the advantages of the SDSNA in terms of its physical properties. Under the same experimental conditions, the SDSNA has a lower root-mean-square error of source location, thus indicating better performance in terms of both DOA and distance estimation.

Ultrastrong to nearly deep-strong magnon-magnon coupling with a high degree of freedom in synthetic antiferromagnets

Ultrastrong and deep-strong coupling are two coupling regimes rich in intriguing physical phenomena. Recently, hybrid magnonic systems have emerged as promising candidates for exploring these regimes, owing to their unique advantages in quantum engineering. However, because of the relatively weak coupling between magnons and other quasiparticles, ultrastrong coupling is predominantly realized at cryogenic temperatures, while deep-strong coupling remains to be explored. In our work, we achieve both theoretical and experimental realization of room-temperature ultrastrong magnon-magnon coupling in synthetic antiferromagnets with intrinsic asymmetry of magnetic anisotropy. Unlike most ultrastrong coupling systems, where the counter-rotating coupling strength g2 is strictly equal to the co-rotating coupling strength g1, our systems allow for highly tunable g1 and g2. This high degree of freedom also enables the realization of normalized g1 or g2 larger than 0.5. Particularly, our experimental findings reveal that the maximum observed g1 is nearly identical to the bare frequency, with g1/ω0 = 0.963, indicating a close realization of deep-strong coupling within our hybrid magnonic systems. Our results highlight synthetic antiferromagnets as platforms for exploring unconventional ultrastrong and even deep-strong coupling regimes, facilitating the further exploration of quantum phenomena.